DEPARTMENT OF THE INTERIOR U.S. GEOLOGICAL SURVEY PETROLEUM GEOLOGY AND HYDROCARBON PLAYS OF THE PERMIAN BASIN PETROLEUM PROVINCE WEST TEXAS AND SOUTHEAST NEW MEXICO by Keith Robinson ; Open-File Report 88-450Z This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards and stratigraphic nomenclature. ^.S. Geological Survey, MS 940, Box 25046, Denver Federal Center, Denver, CO 80225 CONTENTS Page Introduction ......................................................... 1 Geologic Framework and Structural Setting............................. 6 Stratigraphy.......................................................... 9 Older Paleozoic Systems.......................................... 17 Carboniferous System............................................. 17 Permian System................................................... 18 Source Rocks.......................................................... 18 Burial History, Thermal Maturity, and Migration....................... 19 Hydrocarbon Occurrence................................................ 21 Older Paleozoic Systems.......................................... 21 Carboniferous System............................................. 25 Permian System................................................... 25 Data Sources and Analysis............................................. 26 Play Identification................................................... 26 Principal Plays....................................................... 27 Play 1: Delaware Sandstone - Upper Permian........................ 27 Play 2: Northwestern Shelf - Pennsylvanian and Permian Sequence... 29 Play 3: Central Basin Platform - Upper Pennsylvanian - Permian Sequence................ 31 Play 4: Spraberry/Dean Sandstone - Lower Permian.................. 34 Play 5: Delaware and Val Verde Basin Gas - Pennsylvanian - Lower Permian Sequence................ 37 Play 6: Eastern Shelf and Midland Basin - Pennsylvanian and Permian Shelf Sequence.............. 39 Play 7: Horseshoe Atoll - Pennsylvanian........................... 41 Play 8: Northwestern Shelf and Eastern Shelf - Older Paleozoics.. 44 Play 9: Central Basin Platform and Midland Basin - Older Paleozoics...................................... 46 Play 10: Deep Delaware and Val Verde Basin Gas - Older Paleozoics. 49 References............................................................ 52 ILLUSTRATIONS Figure 1. Index map of the Permian basin, southeast New Mexico and West Texas........................................... 2 2. Structural elements in the Permian basin.................. 3 3. Geologic cross section A-A'............................... 4 4. Structure contour map, top of Precambrian rocks........... 5 5. Index map showing significant geologic features........... 7 6. Tobosa basin, as seen in isopach contours of Simpson (Middle Ordovician) strata........................... 8 7. Generalized stratigraphic and lithologic column showing productive intervals................................. 10 8. Isopach of total sedimentary section, in feet. Contour interval 5,000 feet.................................. 11 9. Geologic map at 5,000 foot depth, Permian basin........... 12 10. Geologic map at 10,000 foot depth, Permian basin.......... 13 11. Geologic map at 15,000 foot depth, Permian basin.......... 14 12. Geologic map at 20,000 foot depth, Permian basin.......... 15 13. Geologic map at 25,000 foot depth, Permian basin.......... 16 ILLUSTRATIONS (continued) Page 14. Generalized north-south cross section showing oil- and gas-generating conditions in Delaware basin............... 20 15a. Simplified geologic age relations of the principal oil- producing stratigraphic units of the North-Central, Panhandle, and Vest Texas basins..................... 22 15b. Vertical distribution of occurrence of discovered hydro­ carbons in-place, Permian basin...................... 23 16. Location map, Play 1: Delaware Sandstone - Upper Permian.............................................. 28 17. Location map, Play 2: Northwestern Shelf - Pennsylvanian and Permian Sequence................................. 30 18. Location map, Play 3: Central Basin Platform - Upper Pennsylvanian-Permian................................ 33 19. Location map, Play 4: Spraberry/Dean Sandstone - Lower Permian........................................ 35 20. Location map, Play 5: Delaware and Val Verde Basin Gas - Pennsylvanian - Lower Permian Sequence............... 38 21. Location map, Play 6: Eastern Shelf and Midland Basin - Pennsylvanian and Permian Shelf Sequence............. 40 22. Location map, Play 7: Horseshoe Atoll - Pennsylvanian.... 43 23. Location map, Play 8: Northwestern Shelf and*Eastern Shelf - Older Paleozoics............................. 45 24. Location map, Play 9: Central Basin Platform and Midland Basin - Older Paleozoics............................. 47 25. Location map, Play 10: Deep Delaware and Val Verde Basin Gas - Older Paleozoics......................... 50 11 Introduction The Permian basin is one of the largest Hercynian (Middle Devonian-Middle Triassic) structural basins in North America. It encompasses a surface area in excess of 82,000 mi 2 , which includes all or parts of 52 counties located in West Texas and southeast Nev Mexico (fig. 1). In areal extent, the basin is slightly asymmetrical with the configuration of an irregular shaped octagon, separated into eastern and western halves by a north-south trending central ridge or platform (fig. 2). In cross-section, the basin is an asymmetrical feature, the western half of which contains a thicker and more structurally deformed sequence of sediments than the eastern half (fig. 3). Galley (1958, 1971), and Dolton and others (1979), have characterized the Permian basin as a large structural depression, formed as a result of downwarp in the Precambrian basement surface located at the southern margin of the North American craton. The basin was penecontemporaneously filled with Paleozoic and, to a much lesser extent, younger sediments. It acquired its present structural form by early Permian time and was further accentuated by tectonic activity and downwarping during the Permian and Triassic Periods (fig. 4). This report represents an evolutionary stage in an ongoing process of U.S. Geological Survey resource assessment in west Texas and southeastern New Mexico. The report draws heavily on previous work such as Galley (1971); Dolton and others (1979); Geological Survey Circular 828 (1980); and, most recently, Galloway and others (1983). The discussion of geologic framework closely follows that of Dolton and others, 1979 which arrived at estimates of in-place undiscovered oil and gas. The 1979 estimates were grouped according to geologic age (Permian, Carboniferous, and older Paleozoic) and depth (0-10, 10-20, and greater than 20 thousand feet). These estimates were based on a review of the geologic framework of each major stratigraphic unit assessed and the exploration histories and production statistics through 1976 for all oil and gas accumulations of the Permian Basin equal to or exceeding 1000 bbls oil or 1 million cu ft. gas. The current study uses a more detailed play analysis approach and follows as closely as practical the play definition of Galloway and others 1983. Major differences in objectives and data sets have dictated a number of differences in play characterization by the U.S. Geological Survey and the Texas Bureau of Economic Geology. The Texas Bureau studies focused on oil accumulations (exceeding cumulative productions of 10 million bbls oil that generally have been found earlier in the Permian Basin's exploration history. The U.S. Geological Survey's play analysis considers accumulations of all sizes and the total Permian Basin exploration history. However, the objective of estimating undiscovered recoverable hydrocarbons in plays focuses on the more recent exploration history and therefore on smaller fields (lower cut-off limits are 1 million bbls oil and 6 billion cu ft. gas. Fields smaller than the lower cut-off limit were assessed separately. The general geologic framework and structural development of the Permian basin is extensively documented in the literature. Among others, Galley (1958, 1971); Landes (1970); Hill (1971); Hartman and Woodard (1971); Dolton and others (1979); Wright (1979); Fisher and Galloway (1983); Galloway and others (1983); and Tyler and others (1984), have studied and discussed the Permian bas_in in detail. All these publications contain comprehensive bibliographies. During the compilation of this report, considerable reference to the publications of STUDY AREA 60UNDARY M O « * « O ' -ITCHCI-C i | AWOREWS > I I _ _ _ ___ ;__.__'.- - - - r~-^ ll NEW MEXICO TEXAS; v ,0.,..; . _ _ _ _ . --- 100 150 KILOMETERS 1' 'I ' f T ___U 50 100 MILES Figure 1. Index map of the Permian basin, southeast New Mexico, and west Texas. , I u :.Jig -i <, - VAL V£RDE IH^pl _ 38&&S* ^t1" "^fc_ -fc * - (from Dolton and others, 1979) 100 150 KILOMETERS I_____i 1 ' ' ' I 1 50 MOMHJES EXPLANATION Outline of structuol elements ^ ^- Line of cross section Arch Figured Structural elements in the Permian basin. DELAWARE BASIN MIDLAND BASIN BEND ARCH CENTRAL BASIN EASTERN SHELF PLATFORM FEET JOOQ - 6OOO -, CRETACEOUS »ooo - IOOO - 2OOO - LEVEL QUAOALUPIAN loou - " jooo LEONARD* AN t>OOO ;?uoo - ooix: - 300O - 10 ooo - 1 2 OOO - JOOO - 1OO MILES ! » OOO - t>OOO - 1 fa OOO - CARBONIFEROUS OLDER PALEOZOIC IN PART AFTER HARTMAN AND WOODWARD 1971 (from Dolton and others, 1979) Figure